xref: /linux/drivers/net/fddi/skfp/smttimer.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 /******************************************************************************
2  *
3  *	(C)Copyright 1998,1999 SysKonnect,
4  *	a business unit of Schneider & Koch & Co. Datensysteme GmbH.
5  *
6  *	See the file "skfddi.c" for further information.
7  *
8  *	This program is free software; you can redistribute it and/or modify
9  *	it under the terms of the GNU General Public License as published by
10  *	the Free Software Foundation; either version 2 of the License, or
11  *	(at your option) any later version.
12  *
13  *	The information in this file is provided "AS IS" without warranty.
14  *
15  ******************************************************************************/
16 
17 /*
18 	SMT timer
19 */
20 
21 #include "h/types.h"
22 #include "h/fddi.h"
23 #include "h/smc.h"
24 
25 #ifndef	lint
26 static const char ID_sccs[] = "@(#)smttimer.c	2.4 97/08/04 (C) SK " ;
27 #endif
28 
29 static void timer_done(struct s_smc *smc, int restart);
30 
31 void smt_timer_init(struct s_smc *smc)
32 {
33 	smc->t.st_queue = NULL;
34 	smc->t.st_fast.tm_active = FALSE ;
35 	smc->t.st_fast.tm_next = NULL;
36 	hwt_init(smc) ;
37 }
38 
39 void smt_timer_stop(struct s_smc *smc, struct smt_timer *timer)
40 {
41 	struct smt_timer	**prev ;
42 	struct smt_timer	*tm ;
43 
44 	/*
45 	 * remove timer from queue
46 	 */
47 	timer->tm_active = FALSE ;
48 	if (smc->t.st_queue == timer && !timer->tm_next) {
49 		hwt_stop(smc) ;
50 	}
51 	for (prev = &smc->t.st_queue ; (tm = *prev) ; prev = &tm->tm_next ) {
52 		if (tm == timer) {
53 			*prev = tm->tm_next ;
54 			if (tm->tm_next) {
55 				tm->tm_next->tm_delta += tm->tm_delta ;
56 			}
57 			return ;
58 		}
59 	}
60 }
61 
62 void smt_timer_start(struct s_smc *smc, struct smt_timer *timer, u_long time,
63 		     u_long token)
64 {
65 	struct smt_timer	**prev ;
66 	struct smt_timer	*tm ;
67 	u_long			delta = 0 ;
68 
69 	time /= 16 ;		/* input is uS, clock ticks are 16uS */
70 	if (!time)
71 		time = 1 ;
72 	smt_timer_stop(smc,timer) ;
73 	timer->tm_smc = smc ;
74 	timer->tm_token = token ;
75 	timer->tm_active = TRUE ;
76 	if (!smc->t.st_queue) {
77 		smc->t.st_queue = timer ;
78 		timer->tm_next = NULL;
79 		timer->tm_delta = time ;
80 		hwt_start(smc,time) ;
81 		return ;
82 	}
83 	/*
84 	 * timer correction
85 	 */
86 	timer_done(smc,0) ;
87 
88 	/*
89 	 * find position in queue
90 	 */
91 	delta = 0 ;
92 	for (prev = &smc->t.st_queue ; (tm = *prev) ; prev = &tm->tm_next ) {
93 		if (delta + tm->tm_delta > time) {
94 			break ;
95 		}
96 		delta += tm->tm_delta ;
97 	}
98 	/* insert in queue */
99 	*prev = timer ;
100 	timer->tm_next = tm ;
101 	timer->tm_delta = time - delta ;
102 	if (tm)
103 		tm->tm_delta -= timer->tm_delta ;
104 	/*
105 	 * start new with first
106 	 */
107 	hwt_start(smc,smc->t.st_queue->tm_delta) ;
108 }
109 
110 void smt_force_irq(struct s_smc *smc)
111 {
112 	smt_timer_start(smc,&smc->t.st_fast,32L, EV_TOKEN(EVENT_SMT,SM_FAST));
113 }
114 
115 void smt_timer_done(struct s_smc *smc)
116 {
117 	timer_done(smc,1) ;
118 }
119 
120 static void timer_done(struct s_smc *smc, int restart)
121 {
122 	u_long			delta ;
123 	struct smt_timer	*tm ;
124 	struct smt_timer	*next ;
125 	struct smt_timer	**last ;
126 	int			done = 0 ;
127 
128 	delta = hwt_read(smc) ;
129 	last = &smc->t.st_queue ;
130 	tm = smc->t.st_queue ;
131 	while (tm && !done) {
132 		if (delta >= tm->tm_delta) {
133 			tm->tm_active = FALSE ;
134 			delta -= tm->tm_delta ;
135 			last = &tm->tm_next ;
136 			tm = tm->tm_next ;
137 		}
138 		else {
139 			tm->tm_delta -= delta ;
140 			delta = 0 ;
141 			done = 1 ;
142 		}
143 	}
144 	*last = NULL;
145 	next = smc->t.st_queue ;
146 	smc->t.st_queue = tm ;
147 
148 	for ( tm = next ; tm ; tm = next) {
149 		next = tm->tm_next ;
150 		timer_event(smc,tm->tm_token) ;
151 	}
152 
153 	if (restart && smc->t.st_queue)
154 		hwt_start(smc,smc->t.st_queue->tm_delta) ;
155 }
156 
157